Well, the fact that ND has refused bowl bids in the "modern era" pretty much makes my point for me. They're not beholden to a conference with a multi-party post-season contract, so they don't have to accept a bowl bid if they don't want to. And they obviously have enough money they feel like they can afford to miss a bowl, because they DID make that choice to miss a bowl. Proof's in the pudding, as they say.
Teams in major conferences don't have that kind of freedom. The structure of the conference revenue payouts just won't allow it. They really can't turn down a bowl bid even if they're technically "allowed" to do so. Additionally, the vast majority of head coaches are unlikely to turn down the extra practice time.